/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.core;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletResponse;

import org.apache.catalina.CometEvent;
import org.apache.catalina.Host;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.util.StringManager;
import org.apache.catalina.valves.ValveBase;

/**
 * Valve that implements the default basic behavior for the
 * <code>StandardEngine</code> container implementation.
 * <p>
 * <b>USAGE CONSTRAINT</b>: This implementation is likely to be useful only
 * when processing HTTP requests.
 * 
 * @author Craig R. McClanahan
 * @version $Revision: 467222 $ $Date: 2006-10-24 11:17:11 +0800 (星期二, 24 十月
 *          2006) $
 */

final class StandardEngineValve extends ValveBase {

	// ----------------------------------------------------- Instance Variables

	/**
	 * The descriptive information related to this implementation.
	 */
	private static final String info = "org.apache.catalina.core.StandardEngineValve/1.0";

	/**
	 * The string manager for this package.
	 */
	private static final StringManager sm = StringManager
			.getManager(Constants.Package);

	// ------------------------------------------------------------- Properties

	/**
	 * Return descriptive information about this Valve implementation.
	 */
	public String getInfo() {

		return (info);

	}

	// --------------------------------------------------------- Public Methods

	/**
	 * Select the appropriate child Host to process this request, based on the
	 * requested server name. If no matching Host can be found, return an
	 * appropriate HTTP error.
	 * 
	 * @param request
	 *            Request to be processed
	 * @param response
	 *            Response to be produced
	 * @param valveContext
	 *            Valve context used to forward to the next Valve
	 * 
	 * @exception IOException
	 *                if an input/output error occurred
	 * @exception ServletException
	 *                if a servlet error occurred
	 */
	public final void invoke(Request request, Response response)
			throws IOException, ServletException {

		// Select the Host to be used for this Request
		Host host = request.getHost();
		if (host == null) {
			response.sendError(HttpServletResponse.SC_BAD_REQUEST,
					sm.getString("standardEngine.noHost", request
							.getServerName()));
			return;
		}

		// Ask this Host to process this request
		host.getPipeline().getFirst().invoke(request, response);

	}

	/**
	 * Process Comet event.
	 * 
	 * @param request
	 *            Request to be processed
	 * @param response
	 *            Response to be produced
	 * @param valveContext
	 *            Valve context used to forward to the next Valve
	 * 
	 * @exception IOException
	 *                if an input/output error occurred
	 * @exception ServletException
	 *                if a servlet error occurred
	 */
	public final void event(Request request, Response response, CometEvent event)
			throws IOException, ServletException {

		// Ask this Host to process this request
		request.getHost().getPipeline().getFirst().event(request, response,
				event);

	}

}
